Heart rate variability in patients with orthotopic heart transplantation: long-term follow-up

Cardiac Auscultation for Noncardiologists: Application in Cardiac Rehabilitation Programs: PART II: ADULT PATIENTS AFTER HEART SURGERY

This clinical skills review describes the most common cardiac auscultatory findings in adults after heart surgery and correlates them with prognostic indicators. It was written for noncardiologist health care providers who work in outpatient cardiac rehabilitation programs.Mechanical prosthetic valves produce typical closing and opening clicks. Listening to their timing and features, as well as to presence and quality of murmurs, contributes to the awareness of potential prosthesis malfunction before other dramatic clinical signs or symptoms become evident. In patients with biological prostheses, murmurs should be carefully evaluated to rule out both valve malfunction and degeneration. Rubs of post-pericardiotomy pericarditis should prompt further investigation for early signs of cardiac tamponade. Third and fourth heart sounds and systolic murmurs in anemic patients should be differentiated from pathological conditions. Relatively new groups of heart surgery patients are those with chronic heart failure treated with continuous-flow left ventricle assist devices. These devices produce characteristic continuous noise that may suddenly disappear or vary in quality and intensity with device malfunction. After heart transplantation, a carefully performed and regularly repeated cardiac auscultation may contribute to suspicion of impending acute rejection. During cardiac rehabilitation, periodic cardiac auscultation may provide useful information regarding clinical-hemodynamic status and allow detection of heralding signs of possible complications in an efficient and low-cost manner.

The relationship between physical activity and heart rate variability in orthotopic heart transplant recipients

AIMS AND OBJECTIVES

To investigate the relationship between physical activity and heart rate variability in orthotopic heart transplant recipients, to compare the difference in heart rate variability between patients one year after orthotopic heart transplant and healthy adults matched to the heart transplant recipients in terms of age, gender and physical activity levels.

BACKGROUND

Although physical activity affects the heart rate variability in patients with heart disease, there is a paucity of literature discussing the correlation between physical activity and heart rate variability among heart transplant recipients.

DESIGN

This was a descriptive and cross-sectional study.

METHODS

A total of 120 eligible subjects were divided into the orthotopic heart transplant recipient group (n = 60) and the healthy adult group (n = 60). The Seven-day Physical Activity Recall questionnaire was used to record the subjects' amount of physical activity per week. Heart rate variety parameters were determined by separate frequency domain components.

RESULTS

Results indicated heart transplant recipients' heart rate variety was significantly lower than that of healthy adults in terms of mean, sdr, total power (ms(2)), low frequency (ms(2)), low frequency (nu), high frequency (ms(2)) and low frequency/high frequency. Heart transplant recipients' heart rate variety including total power (ms(2)), low frequency (ms(2)) and high frequency (ms(2)) was 18·2, 2 and 7·2% of healthy controls, respectively; the amount of absolutely and relatively moderate physical activity was positively related to high frequency (ms(2)) and high frequency (nu), but was negatively related to low frequency/high frequency. High frequency (nu) increases while the total amount of weekly physical activity increases.

CONCLUSIONS

Results confirmed that the more the moderate physical activity performed, the better the patient's heart rate variability.

RELEVANCE TO CLINICAL PRACTICE

We suggest that clinical care providers have to encourage heart transplant recipients to engage in moderate physical activity.

Analysis of heart rate variability using time-varying filtering of heart transplanted patients

In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing.

Evolution of heart rate control after transplantation: conduction versus autonomic innervation

In cardiac transplantation, the donor organ is not initially innervated and demonstrates decreased heart rate variability (HRV). However, HRV may improve after several months. The mechanism for HRV improvement has not been elucidated; autonomic "reinnervation" of the donor heart has been proposed. The role of atrioatrial conduction from recipient to donor organ has not been evaluated. We prospectively evaluated cardiac transplant patients with a limited electrophysiology study at the time of their surveillance biopsies. Recordings were made of recipient and donor signals, observing conduction properties between recipient and donor atria. Holter recordings were analyzed and HRV was determined using spectral analysis techniques, recording mean RR interval, low-frequency power (LF), high-frequency power (HF), and the LF/HF ratio. These were compared to published norms. From November 1999 to May 2000, 21 patients (6 female) who underwent cardiac transplantation participated at a median age of 101 months (range, 4.1-217 months). Time posttransplant ranged from 26 days to 71 months. Holter data were available for 20 patients and demonstrated dissociated P waves in 13 (65%). The mean heart rate on Holter was 111 beats per minute (bpm) (range, 85-161 bpm). We were able to record distinct recipient atrial signals in 16 of 21 (76%) patients. The average recipient tissue heart rate was 55% that of the donor heart rate. We documented atrioatrial association in only 1 patient. HRV did not reach normal values for most patients and did not increase with time posttransplantation. The LF values were in the normal range for most patients, whereas 3 patients had normal HF values and 2 patients had values just below normal. Recipients of heart transplantation have a predominantly sympathetic influence of HRV. These preliminary data suggest that atrioatrial conduction does not play a role in reestablishing normal heart rate control following pediatric cardiac transplantation.

Heart rate variability in healthy children and adolescents is partially related to age and gender

We evaluated 24-h time-domain heart rate variability (HRV) in 103 (46 females) healthy children and adolescents. Subjects were divided into four male and four female groups (ages 1-5, 6-10, 11-15, 16-20 years) and 24-h ambulatory Holter monitoring was performed. HRV was assessed by SDNN, SDNN index (SDNN-i), SDANN, rMSSD, pNN50. Males showed SDNN and SDANN values significantly higher than females while for SDNN-i, rMSSD, pNN50 there were no significant differences between sexes. With increasing age, there is a progressive and significant decrease of HR and increase of SDANN. On the other hand, SDNN, SDNNi, pNN50 and rMSSD increased significantly only between the first two age-groups. rMSSD and pNN50 were significantly related to body mass index. Thus, SDNN and SDANN, overall HRV measures, increased with age and were gender-related. HRV indices of parasympathetic function (rMSSD, pNN50) and SDNN-i increased up to 10 years of age and were gender-unrelated. These data demonstrate that in healthy children and adolescents there is a progressive modification of HRV that may reflect a progressive evolution of the autonomic nervous system, with different pattern measure-dependent. This paper enables us to compare, in future works, HRV in pediatric subjects in different groups according to the different HRV measures under examination.

Incidence and prognostic value of electrocardiographic abnormalities after heart transplantation

BACKGROUND

The improvement of surgical techniques and the use of immunosuppressive drugs within the past 15 years has made heart transplantation an increasingly performed procedure and an accepted treatment for end-stage cardiac failure.

HYPOTHESIS

The aim of this study was to describe the changes of the 12-lead electrocardiogram (ECG) after heart transplantation and to determine their prognostic value on complications such as rejection or graft coronary artery disease during follow-up.

METHODS

The ECGs of 62 consecutive patients were analyzed for 5 years at follow-up periods of 1, 2, 3, 6 months and yearly after transplantation.

RESULTS

The most prevalent abnormality was the presence of complete or incomplete right bundle-branch block (RBBB). New RBBB appeared in 69% (43/62) of the patients, mainly during the first month (21/43). There was no left bundle-branch block. We detected nine episodes of supraventricular arrhythmias: one atrial fibrillation, six atrial flutter, one junctional tachycardia, one orthodromic tachycardia on a Wolff-Parkinson-White syndrome; all appearing during the first 3 months. Three of the six episodes of atrial flutter occurred during an episode of acute rejection. There was no relation between RBBB and the gender and age of recipients and donors, nor with the graft ischemic time and the pretransplantation hemodynamic values. Right bundle-branch block was not associated with acute rejection nor with graft coronary artery disease.

CONCLUSION

The ECG abnormalities after heart transplantation have no predictive value on the long-term evolution. Right bundle-branch block is very frequent and is not associated with adverse prognosis.

Heart rate variability after cardiac transplantation in humans

The reappearance of cardiac innervation after cardiac transplantation remains a matter of debate. We evaluated the ability of heart rate variability (HRV) analysis to detect the extent and time course of functional cardiac allograft reinnervation. Time- and frequency-domain analysis of heart rate was performed on Holter recordings of 120 heart transplant and four heart-lung transplant recipients. A high frequency (HF) component was clearly distinguished on visual inspection of power spectral density in 42 patients. In eight patients an HF component of normal magnitude was detected. The other 34 patients in this group, including all four heart-lung transplants, presented with a very small HF component. The other 82 patients showed a flat spectrum. The group with an HF component of normal amplitude was significantly different, compared to the other groups, for all HRV parameters. Serial plotting of HRV parameters of the patients with an HF component of normal amplitude against time posttransplant, revealed, from 12 months onwards, a progressive increase of parameters denoting HF variability. In five heart transplant patients with acute allograft rejection, the use of HRV analysis for rejection monitoring was unsuccessful. These results suggest that, inasmuch as the HF component of HRV is caused by parasympathetic cardiac innervation, the HF component of normal amplitude, observed in only a minority of cardiac transplant recipients (6%), is a marker for parasympathetic reinnervation. The evolution over time of this HF component is compatible with a biological phenomenon as gradual parasympathetic reinnervation of the sinus node.